Small Craft Advisory 90, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
550 AM AKST MON JAN 25 2016

.SHORT TERM.../MONDAY THROUGH TUESDAY/ THE MAIN FOCUS OF THE SHORT
RANGE TODAY IS THE GALE FORCE FRONT THAT WILL AFFECT THE PANHANDLE
THROUGH AT LEAST TUESDAY. SAID FRONT IS CURRENTLY SITUATED JUST
OFFSHORE OF THE PANHANDLE AND IS BRINGING RAIN AND SOME BREEZY
WINDS TO THE PANHANDLE THIS MORNING. HIGHEST WINDS REMAIN OFFSHORE
THIS MORNING WITH GUSTS TO 35 KT MEASURED AT SOME OF THE OFFSHORE
BUOYS. AS FOR LAND AREAS, HIGHEST GUSTS SO FAR ARE AT SITKA WITH
A GUST TO 32 KT AROUND 5 AM. SOUTHERLY WINDS HAVE KEPT
TEMPERATURES IN THE MID 30S TO MID 40S FOR MOST OF THE PANHANDLE
SO RAIN IS THE MAIN P-TYPE ACROSS THE AREA. THE EXCEPTIONS ARE THE
UPPER REACHES OF THE HAINES HIGHWAY, ALL OF THE KLONDIKE HIGHWAY
(INCLUDING SKAGWAY WHERE CALM WINDS HAVE ALLOWED SNOW MELT COOLING
TO TAKE PLACE) AND HYDER. TEMPERATURES REMAIN COLD ENOUGH FOR SNOW
IN THESE PLACES AND PRECIP RATES ARE HIGH ENOUGH AND TEMPS COLD
ENOUGH FOR A WINTER STORM WARNING TO CONTINUE FOR THE WHITE PASS
AREA OF THE KLONDIKE HIGHWAY TODAY.

THE FRONT WILL LINGER OFFSHORE THROUGH TODAY AND INTO TONIGHT AS A
STRONG SHORT WAVE DEVELOPS ALONG THE FRONT SW OF HAIDA GWAII THIS
AFTERNOON AND MOVES NORTHWARD THROUGH THE EASTERN GULF TONIGHT.
SHORT RANGE MODELS ARE HAVING A TERRIBLE TIME TRYING TO PIN THE
STRUCTURE AND TIMING OF THE SHORT WAVE DOWN. THE ECMWF AND
CANADIAN MODELS ARE BY FAR THE FASTEST WITH TIMING HAVING THE WAVE
BE OVER THE NORTHEAST GULF COAST AS EARLY AS 12Z TUE. THE GFS IS
SORT OF THE MIDDLE GROUND AND ABOUT 3 HOURS SLOWER THEN THE ECMWF
AND CANADIAN. THE NAM IS SLOWER THEN ALL THE REST AND LINGERS THE
LOW IN THE NE GULF THROUGH AT LEAST TUE MORNING.

AS A RESULT THE WIND FORECAST PARTICULARLY THE TIMING OF THE
HIGHEST WINDS FOR TONIGHT IS RATHER UNCERTAIN. ALL THE MODELS ARE
DEPICTING LOW LEVEL JET STRENGTH OVER THE SOUTHERN PANHANDLE AND
OUTER COAST REACHING 70 TO 80 KT OR MORE MON NIGHT. SO DECIDED TO
UPGRADE THE HIGH WIND WATCHES TO WARNINGS FOR ZONES 23, 27, AND
28. THE DECISION ON TIMING WENT TO THE GFS AND ECMWF AS BOTH WERE
SOMEWHAT CLOSE ON TIMING OF THE HIGHER WINDS LATER THIS EVENING
INTO LATE TONIGHT AND HAD SOME SUPPORT FROM OTHER MODELS. HOWEVER
IF THE SLOWER TIMING OF THE NAM PANS OUT HIGH WINDS COULD
POTENTIALLY START LATER AND LAST INTO TUE MORNING FOR THE WARNED
AREA. THE NEW 12Z RUN OF THE NAM HAS CAST SOME DOUBT ON THE 6Z
RUN'S SLOWER SOLUTION HOWEVER, AS IT HAS SPED UP THE WAVE.

OTHERWISE THE NEXT 36 HOURS WILL BE WET AND WARM. SOUTHERLY WINDS
WILL KEEP TEMPERATURES IN THE MID 30S TO MID 40S FOR MOST AREAS.
RAIN WILL BE THE DOMINATE P-TYPE. ONLY THE UPPER REACHES OF THE
HAINES AND KLONDIKE HIGHWAYS WILL SEE SNOW AND EVEN THEN TEMPS MAY
GET WARM ENOUGH FOR SOME RAIN TO MIX IN LIMITING SNOW AMOUNTS IN
THESE AREAS. AS A RESULT DID NOT CHANGE THE WHITE PASS WINTER
STORM WARNING FROM IT CURRENT ENDING TIME OF 4 PM. PRECIP WILL
DIMINISH AND WINDS WILL DIMINISH AND TURN SW INTO TUE AS THE
FRONT PUSHES ITS WAY EASTWARD IN THE WAKE OF THE SHORT WAVE.

.LONG TERM.../TUESDAY NIGHT THROUGH SUNDAY/ ACTIVE WEATHER
CONTINUES THROUGH THE END OF WEEK WITH ANOTHER POTENTIAL STORM
FORCE LOW MOVING IN TO BEFORE TRANSITIONING TO A WEAKER PATTERN
WITH HIGH PRESSURE BUILDING OVER THE NE PACIFIC. OVERALL GFS/ECMWF
IN GENERAL AGREEMENT WITH SYNOPTIC PATTERN WITH NAM/GEM AS
OUTLIERS EARLY ON. MORE MODEL SPREAD OCCURS BY LATE WEDNESDAY INTO
TUESDAY WITH THE NEXT GULF LOW SO EXPECT SOME TIMING/STRENGTH
CHANGES TO OCCUR WITH UPDATED FORECASTS.

AS THE CURRENT SYSTEM MOVES NORTHWARD AND DISSIPATES THE NEXT LOW
WILL TRACKING SOUTH OF THE ALEUTIANS MOVING INTO THE WESTERN GULF
THEN SWING NORTH TOWARDS KODIAK. THE ASSOCIATED OCCLUDED WEATHER
FRONT PUSHES INTO THE EASTERN GULF TUESDAY EVENING INTO WEDNESDAY.
THE LOW CENTER WILL WEAKEN THROUGH WEDNESDAY NIGHT AND THURSDAY
AS IT MOVES INTO THE NORTHWEST GULF AS HIGH PRESSURE RIDGE BUILDS
INTO THE WESTERN AK GULF.

ANOTHER ROUND OF WINDS HITS THE GULF ALONG THE FRONT WITH
POTENTIAL STORM FORCE BARRIER JET FORMING IN PKZ052 WITH GALES
EXTENDING DOWN TO PZK041. AS THE LOW CENTER WILL BE FURTHER WEST
THEN CURRENT WIND PRODUCING EVENT NOT EXPECTING OVERLAND WINDS TO
BE AS HIGH. 60-70 KT 925 MB LLJ LOSES ENERGY BUY THE TIME THE
FRONT HITS THE PANHANDLE COAST. INNER CHANNEL WINDS WILL HAVE A
QUICK SPEED AND DIRECTION SHIFT AS WELL BETWEEN THE TWO SYSTEMS,
FLIPPING N BY WEDNESDAY THEN BACK S WITH THE PASSING FRONT.

MORE HEAVY PRECIP WITH WARM SOUTHERLY FLOW FOR MOST OF THE
PANHANDLE. 6 HOUR QPF VALUES NEARING HALF AN INCH FOR WEDNESDAY.
FOR NOW ONLY HAINES AND KLONDIKE HIGHWAYS SEE TO STAY COLD ENOUGH
FOR SNOW, AND POTENTIAL OF ADVY TO WARNING AMOUNTS AT THE BORDERS.

BY THE WEEKEND HIGH PRESSURE BUILDING OVER THE GULF WILL KEEP
ONSHORE FLOW AND PRECIP LASTING INTO FRIDAY AND MOST OF SATURDAY,
BUT WITH MUCH LOWER QPF AND LIGHTER WINDS DUE TO WEAKER GRADIENT.
AS OF NOW BOTH ECMWF/GFS INDICATE THIS DRY PERIOD, SO EXPECT
INCREASING CONFIDENCE IF NEW RUNS KEEP THE TREND.

WITH THE EXCEPTION OF THE VARIATION ON THE WEDNESDAY LOW TIMING
AND STRENGTH THE ECMWF/GFS HAS BEEN IN GOOD AGREEMENT WHILE
NAM/GEM WERE OFF ON THEIR OWN. AS THE INHERITED GIRD GAVE GOOD
REPRESENTATION OF EXPECTED SYNOPTIC PATTERN LEFT THEM MOSTLY AS
IT. GOT SOME DIRECTION CHANGES DUE TO PARALLEL GRADIENT SHOWING
BIT MORE NORTHERLY INFLUENCES. FORECAST CONFIDENCE IS AVERAGE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WARNING FROM 6 PM THIS EVENING TO 5 AM AKST TUESDAY
     FOR AKZ027-028.
     HIGH WIND WARNING FROM 9 PM THIS EVENING TO 5 AM AKST TUESDAY
     FOR AKZ023.
     STRONG WIND TONIGHT FOR AKZ024-026.
     STRONG WIND FROM TODAY THROUGH TONIGHT FOR AKZ022.
     WINTER STORM WARNING UNTIL 4 PM AKST THIS AFTERNOON FOR AKZ018.
MARINE...STORM WARNING FOR PKZ036-041.
     GALE WARNING FOR PKZ031>035-042-043-051-052.
     SMALL CRAFT ADVISORY FOR PKZ011-013-021-022-053.
&&

EAL/PRB

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